(Partially) implement LD instruction.

1 files changed, 35 insertions, 6 deletions

diff --git a/asm.myr b/asm.myr
index 4f6e1b4..0235db5 100644
--- a/asm.myr
+++ b/asm.myr
@@ -40,8 +40,11 @@ type literal = union
     `Number int
     `Register int
     `Label byte[:]
-    `DerefAddr int
-    `DerefLabel byte[:]
+    `DerefAddr
+    `Keypress
+    `AddressRegister
+    `DelayTimer
+    `SoundTimer
     `Invalid
 ;;
 
@@ -63,10 +66,15 @@ const parselit = {s
         |`std.None: -> `Invalid
         ;;
     elif s[0] == ('[' : byte)
-        match getnum(s[:s.len-1])
-        |`std.Some(n): -> `DerefAddr(n)
-        |`std.None: -> `DerefLabel(s[:s.len-1])
-        ;;
+        -> `DerefAddr
+    elif s[0] == ('K' : byte)
+        -> `Keypress
+    elif s[0] == ('I' : byte)
+        -> `AddressRegister
+    elif s[0] == ('D' : byte)
+        -> `DelayTimer
+    elif s[0] == ('S' : byte)
+        -> `SoundTimer
     else
         -> `Label(s)
     ;;
@@ -170,6 +178,27 @@ const emitinstr = {p
         | _:
             -> `std.Err(std.fmt("invalid argument to SKNP: {}", p[1]))
         ;;
+    | "LD":
+        if p.len < 3
+            -> `std.Err("LD missing arguments")
+        ;;
+        match (parselit(p[1]), parselit(p[2]))
+        | (`Register(n), `Keypress): b = `std.Some([0xf0 | (n & 0x0f), 0x0a])
+        | (`Register(m), `Number(n)): b = `std.Some([0x60 | (m & 0x0f), (n & 0xff)])
+        | (`Register(m), `Label(l)): b = `std.Some([0x60 | (m & 0x0f), 00])
+            mark = `std.Some(strdup(l))
+        | (`Register(m), `Register(n)): b = `std.Some([0x80 | (n & 0x0f), (m & 0x0f) << 1])
+        | (`Register(n), `DelayTimer): b = `std.Some([0xf0 | (n & 0x0f), 0x07])
+        | (`DelayTimer, `Register(n)): b = `std.Some([0xf0 | (n & 0x0f), 0x15])
+        | (`SoundTimer, `Register(n)): b = `std.Some([0xf0 | (n & 0x0f), 0x18])
+        | (`AddressRegister, `Number(n)): b = `std.Some([0xa0 | (n & 0x0f), (n & 0xff)])
+        | (`AddressRegister, `Label(l)): b = `std.Some([0xa0, 0x00])
+            mark = `std.Some(strdup(l))
+        | (`DerefAddr, `Register(n)): b = `std.Some([0xf0 | (n & 0x0f), 0x55])
+        | (`Register(n), `DerefAddr): b = `std.Some([0xf0 | (n & 0x0f), 0x65])
+        | _:
+            -> `std.Err(std.fmt("invalid argument to LD: {}", p[1]))
+        ;;
     | _:
         -> `std.Err(std.fmt("unrecognized instruction {}", p[0]))
     ;;